Printed materials such as maps, artwork, advertising, computer printouts, posters and instructional materials benefit from being encapsulated between sheets of clear plastic film. The encapsulation protects the printed material from moisture and soil. It also renders the printed matter less subject to wrinkles, tears and other forms of abuse to which well-used printed materials are often subjected. Clear plastic lamination also improves the appearance of the laminated article giving it a clear, glossy or matte finish. Encapsulation between clear plastic film is a process which an end user of a map or the like may apply to a single copy of a map or other printed work as the user's need for durable copies of improved appearance dictates. Encapsulation of printed materials is also a service sometimes provided to end users by local small businesses which handle jobs as small as a single item to be encapsulated.
Encapsulation of printed documents between plastic sheets allows small- and medium-size printers to supply their full range of printing capabilities in a format with the durability of plastic, this durability being provided by the use of a single additional machine. Thus, a small or medium printer can provide all the capabilities of his printing presses in a durable format with relatively little additional capital cost.
The encapsulation process is normally performed on a machine which has opposed heated rollers. Two sheets of opposed polyester film with a heat-activated adhesive on the opposed faces are wrapped around the heated cylinders where they are Pre-heated and fed through a nip between the heated cylinders. The printed material to be laminated is simultaneously fed through the nip and encapsulated between the two opposed films.
These known laminators have problems associated with single sheet feeding. Once a sheet has been started and gripped by the nip between the laminated rollers, it cannot be adjusted to assure alignment with the laminating films. Thus, any error in alignment may result in the sheet being laminated failing to stay within the confines of the laminating films. Further, the leading edge of the sheet of paper being fed into the nip must be perfectly flat, or the progression of the sheet through the rollers will produce wrinkles. Once engaged by the nip, the sheet cannot be effectively aligned. It is also undesirable for an operator to place his fingers too close to the heated nip.
What is needed is a laminator for encapsulating sheet articles which allows the article to be positioned between the sheets of laminating film sufficiently before the heated laminating rollers to assure proper alignment, to prevent wrinkles and ensure operator safety.